Elevated endothelin-1 levels impair nitric oxide homeostasis through a PKC-dependent pathway

Article; Proceedings Paper

关键词: ARTERIAL SMOOTH-MUSCLE;    PROTEIN-KINASE-C;    PLASMA ENDOTHELIN;    CORONARY;    DYSFUNCTION;    ANTAGONISM;    EXPRESSION;    DISEASE;   

DOI  :  10.1161/CIRCULATIONAHA.105.001503

来源: SCIE

【 摘 要 】

Background-Endothelin-1 (ET-1) plays an important role in the maintenance of vascular tone and pathological states such as ischemia/reperfusion (I/R) injury, coronary vasospasm, and cardiac allograft vasculopathy. We assessed the effects of elevated ET-1 levels as seen after I/R to determine if ET-1 modulates nitric oxide ( NO) production via the translocation of specific protein kinase C (PKC) isoforms. Methods and Results-Human saphenous vein endothelial cells (HSVECs) (n = 8) were incubated with ET-1 or phosphate-buffered saline (PBS) for 24 hours. NO production was determined in the supernatant by measuring nitrate/nitrite levels. Protein expression of endothelial nitric oxide synthase (eNOS), inducible NOS (iNOS), caveolin-1 and PKC were determined. Lastly, PKC translocation and activity were assessed after exposure to the drug of interest. HSVECs exposed to ET-1 displayed decreased NO production. PKC inhibition reduced NO production, whereas PKC activation increased production. NO production was maintained when HSVECs exposed to ET-1 were treated with the PKC agonist, PMA. eNOS protein expression was reduced after ET-1 treatment. PKC inhibition also downregulated eNOS protein expression, whereas PMA upregulated expression. ET-1 exposure led to a significant increase in PKC delta and PKC epsilon translocation compared with control, whereas translocation of PKC lambda was inhibited. ET-1 exposure significantly reduced overall PKC activity compared with control. Conclusions-Our study demonstrates that high levels of ET-1 impair endothelial NO production via an isoform-specific PKC-mediated inhibition of eNOS expression. ET-1 antagonism with bosentan stimulates translocation of PKC lambda and leads to increased PKC activity and NO production. ET-1 antagonism may provide a novel therapeutic strategy to improve vascular homeostasis.

【 授权许可】

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